JPH09137285A - Lubricating steel sheet excellent in oil face adhesive property and chemical convertibility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a lubricating steel sheet improved in oil face adhesive properties and furthermore excellent in chemical convertibility. SOLUTION: This lubricating steel sheet is the one in which a film contg. silicic acid or silicate is formed on a steel sheet or a plated steel sheet in which fine ruggedness is present on the surface, the content of SiO2 in the film is regulated to 1 to 200mg/m<2> , and furthermore, in the case the coating weight of SiO2 in the projected part on the surface of the lubricating steel sheet is denoted as A and the coating weight of SiO2 in the recessed part as B, the value of B/A is regulted to >=1.2. Moreover, the weight of Na2 O, K2 O and Li2 O is preferably all regulated to <=3% to the weight of SiO2 in the film. Furthermore, the film is incorporated with the oxide of one or more kinds of elements selected from the group composed of Zn, Ni, Co, Fe, P, B, Ca, Mo, W and V by 1 to 100mg/m<2> as the total weight of each element or is coated with oil having 5 to 50mm<2> /s viscosity at 40 deg.C to improve its lubricity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating steel sheet having excellent oil surface adhesiveness and chemical conversion treatability.

[0002]

2. Description of the Related Art In recent years, the use of surface-treated steel sheets whose surfaces have been plated is increasing. Among them, Zn-plated steel sheets have excellent corrosion resistance. It is commonly used. However,
The problem of galling of the plating and the die has occurred in the parts that are severely processed during press molding. One of the causes of galling is that the sliding deformation resistance applied to the plating surface layer portion by pressing is large.

Therefore, a hard oxide film is formed on the surface of the plated steel sheet for the purpose of reducing sliding deformation resistance in the plating surface layer portion and enhancing slidability, thereby improving lubricity during press forming. The designed plated steel sheet has been developed. For example, Japanese Patent Publication No. 7-13306 discloses Z
A technique of improving lubricity by applying an anhydrous alkali metal salt of an oxide of a semimetal such as B, P, or Si onto n-type plating is disclosed, and JP-A-6-116746 discloses Zn-based plating. A technique for improving the pressability by forming metal oxides in an island shape or a mosaic shape on the plating is disclosed.
Further, in Japanese Patent Publication No. 7-13308, Zn oxide, Mn oxide, P, Mo, W, V are formed on the surface of a Zn-plated steel sheet.
Steel sheet having a coating with one or more oxides of

Further, since the joining process after pressing of an automobile is mainly carried out by spot welding, it is disclosed in JP-A-55-55.
No. 110783 and Japanese Patent Laid-Open No. 60-63394 disclose a plated steel sheet having SiO ₂ deposited on a Zn-based plating layer for the purpose of improving spot weldability of the plated steel sheet.

However, in the automobile manufacturing process, not only the spot welding process but also the step of joining the parts with the adhesive after the press forming is performed. It was found that the adhesiveness with the agent was significantly deteriorated.

Specifically, for example, in a hem portion of a door, a hood, a luggage, etc., joining is performed with an adhesive while oil is still attached. A vinyl chloride-based or epoxy-based adhesive is used as the adhesive, and the adhesive is applied and then baked to join the steel plates to each other. Therefore, if the adhesiveness between the steel sheet and the steel sheet is poor, the interface between the adhesive agent and the steel sheet may be peeled off, resulting in a significant decrease in the strength of the joint.

Further, after the joining process, a chemical conversion treatment such as a phosphate treatment is applied as a pretreatment for coating, but the oxide film formed on the plated steel sheet is dissolved and removed by the degreasing treatment in the previous step of the chemical conversion treatment. However, since it remains on the Zn-plated steel sheet, it is pointed out that it inhibits the formation of normal oxalate crystals during the chemical conversion treatment. That is, there was a problem that chemical conversion treatability was poor. As a result, the adhesion of the coating film was lowered, which was also a factor that deteriorates the corrosion resistance after coating.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a lubricated steel sheet having improved oil surface adhesion and excellent chemical conversion treatability. Is.

[0009]

Means for Solving the Problems According to the present invention capable of solving the above-mentioned problems, a steel or plated steel sheet having fine irregularities on its surface is formed with a film containing silicic acid or silicate. Which is a lubricating steel sheet comprising
With O ₂ is 1 to 200 mg / m ^2, a SiO ₂ adhesion amount of the raised portion of the lubricating steel sheet surface is A, when the SiO ₂ adhesion amount of recess is B, the value of B / A is 1.2
The above is a summary. The total of Na ₂ O, K ₂ O and Li ₂ O contained in the film is
It is desirable that the content is 3% by weight or less with respect to SiO ₂ in the film.

Further, Zn, Ni, Co, F
e, P, B, Ca, Mo, W, V, an oxide of one or more elements selected from the group consisting of 1 by the total weight of each element.
It is possible to improve the lubricity by adding -100 to 100 mg / m ² or by applying an oil having a viscosity of 5 to 50 mm ² / s at 40 ° C.

As the plated steel sheet, a Zn-based plated steel sheet is preferable, and an alloyed molten Z having a Fe content of 7 to 15% is used.
N-plating is recommended. Further, when the center line average roughness Ra of the plated steel sheet surface is 0.5 to 1.5 μm and the PPI is 75 to 300, better lubricity can be obtained. In the present invention, PPI is the number of peaks having a size of 1.27 μm or more contained in 1 inch.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have earnestly conducted research on a method for improving lubricity without deteriorating the oil surface adhesiveness and chemical conversion treatability of a steel plate or a plated steel plate.
As a result, if silicic acid or silicate [hereinafter referred to as silicic acid (salt)] is applied to the surface of the steel plate or the plated steel plate, and SiO ₂ is preferentially attached to the concave portion of the surface, the purpose is The inventors have found that the above can be achieved and have arrived at the present invention.

First, a silicic acid (salt) film coated on the surface of a steel plate or a plated steel plate will be described. The silicic acid (salt) film is a strong hard film composed of fine silica particles, and by forming such a film, the sliding deformation resistance applied to the plating surface layer portion during press working is reduced. be able to. Moreover, silicic acid (salt) is relatively low in price, and has the advantage that the manufacturing cost is low. However, simply coating the surface of the steel sheet or the plated steel sheet with a silicic acid (salt) film is similar to the conventional technique, and the oil surface adhesiveness and the chemical conversion treatment property are deteriorated.

Therefore, the inventors of the present invention investigated various distribution states of the silicic acid (salt) coating on the surface of the steel sheet or the plated steel sheet, and as a result, found that silicic acid (salt) was formed in the recesses on the surface of the steel sheet or the plated steel sheet. It has been found that the preferential adhesion can improve the lubricity without deteriorating the oil surface adhesiveness and the chemical conversion treatment property. The reason can be inferred as follows. That is, the oil surface adhesiveness and chemical conversion treatability of the steel sheet coated with silicic acid (salt) or the galvanized steel sheet depend on the coverage of silicic acid (salt), and even if the silicic acid (salt) is uniformly and firmly coated. In this case, the contact between the steel plate or the plated layer and the adhesive or the chemical conversion treatment liquid becomes insufficient, so that the oil surface adhesiveness and the chemical conversion treatment property deteriorate. On the other hand, by preferentially depositing silicic acid (salt) in the recesses of the steel plate or plating layer and controlling the amount of deposition on the protrusions to a small amount, the steel plate or plating layer and adhesive or The chemical conversion treatment liquid becomes easy to contact,
It is considered that the oil surface adhesive and chemical conversion treatability were dramatically improved. The lubricity is sufficiently good if a certain amount of silicic acid (salt) is present in the recesses.

However, in order to coat the silicic acid (salt) effectively so as to exert the lubricating action without deteriorating the oil surface adhesiveness and the chemical conversion treatment property, as described above, Si after drying is used.
Apply so that the weight of O ₂ is 1 to 200 mg / m ² ,
Further, the ratio B / A of the SiO ₂ adhesion amount A on the convex portion of the steel plate or the plated steel plate and the SiO ₂ adhesion amount B on the concave portion
Must be 1.2 or more. The reason for determining these numerical values will be described with reference to FIGS. 1 and 2.

FIG. 1 shows the relationship between the coating amount of SiO ₂ and the lubricity and oil surface adhesiveness when SiO ₂ is coated on the following alloyed hot dip Zn plated steel sheet. [Alloyed hot dip galvanized steel sheet] Adhesion amount: 60 g / m ² Fe content rate: 11% Surface roughness Ra: 1.0 PPI: 130

The coefficient of friction was used as an index of lubricity, the pull-out load was measured by the following plane sliding test, and the coefficient of friction was calculated from the surface pressure and the pull-out load. [Sample size] 40 x 250 mm [Tool] Flat tool (18 x 20 mm) [Pressure] 5 kg / mm ² [Sliding speed] 300 mm / min [Sliding length] 150 mm [Oil coating] Knoxlast 550 (Parker Kosan Made), 2 g / m ²

The oil surface adhesiveness was evaluated by measuring the T-type tensile peel strength of the steel sheets adhered with an adhesive by the following method. [Sample size] 20 × 200 mm [Oiling] Knoxlast 550 (manufactured by Parker Kosan), 2 g / m ² [Adhesive] Vinyl chloride PV5306 (manufactured by Henkel Shiramizu) [Adhesion method] Adhesive between two steel plates Insertion, 0.15 mm diameter SUS wire with a pitch of about 30 mm as a spacer and fixing two steel plates with clips etc. [baking] 160 ° C x 10 min [cooling] 20 ° C x humidity of 22% 22 hr Leave [T-type peeling] Tensile speed 200 mm / min [Process] Oil coating → Adhesion → Baking → Cooling → T-type peeling

FIG. 2 shows the relationship between the amount of SiO ₂ applied and the chemical conversion treatability when SiO ₂ is applied to the alloyed hot dip Zn plated steel sheet. The chemical conversion treatability was evaluated as follows. [Chemical conversion treatment liquid] SD5000 (manufactured by Nippon Paint Co., Ltd.) [Process] Degreasing → water washing → surface adjustment → chemical conversion treatment [Judgment of chemical conversion treatment film] The film was observed by SEM and classified according to the following evaluation criteria. ：: Uniform film formation △: Partial film formation ×: No film formation

As is apparent from the graphs of FIGS. 1 and 2, S
It can be seen that when iO ₂ is 1 mg / m ² or more, the friction coefficient is significantly reduced and the lubricity is improved. However, when SiO ₂ exceeds 200 mg / m ² , the oil surface adhesiveness and the chemical conversion treatment property are significantly deteriorated, so the upper limit was made 200 mg / m ² . The preferred lower limit is 10 mg / m ² , 20 m
It is more preferably g / m ² or more. On the other hand, the preferable upper limit value is 100 mg / m ² , and more preferably 60 mg / m ² or less.

FIG. 3 shows an alloyed hot dip galvanized steel sheet with Si
The relationship between the ratio B / A of the SiO ₂ adhered amount A of the convex portion and the SiO ₂ adhered amount B of the concave portion when O ₂ was applied, and the lubricity and the oil surface adhesiveness was investigated. The experimental conditions are substantially the same as the conditions adopted for obtaining the results shown in FIG. 1 above, except that the amount of SiO ₂ adhered was set to 30 mg / m ² , and the lubricity and oil surface adhesion were also the same. evaluated.

Although fine irregularities are present on the surface of the steel sheet or the plated steel sheet, it is impossible to distinguish them by simply observing the concave portions and the convex portions from the surface. Therefore, the profile of the surface roughness is measured, and the portion located above the center line of the obtained roughness curve is defined as the convex portion, and the portion located below is defined as the concave portion. For example, according to the roughness curve an example of which is shown in FIG. 4, the peak (a) portion located above the center line corresponds to the convex portion, and the valley portion (b) located below the center line corresponds to the concave portion.

However, in the case of an alloyed hot dip Zn plated steel sheet, the convex portions are crushed and smoothed by skin pass rolling after plating. Therefore, if it is formed flat portion by skin pass rolling, the SiO ₂ adhesion amount of the flat portion and SiO ₂ adhesion amount A of the protruding portion, SiO ₂ of the other valleys
The adhered amount was defined as the SiO ₂ adhered amount B of the concave portion. The flat portion (convex portion) and the valley portion (concave portion) are formed on the surface of the plating layer by SEM.
Alternatively, it can be easily identified by observing with EPMA. FIG.
Is an EPMA obtained by photographing the surface of the alloyed hot-dip Zn coating layer.
In the photograph, a is a convex portion and b is a concave portion. Ratio of adhered amount of SiO _{2 on the} convex portion and the concave portion B / A
Can be obtained, for example, by measuring the Si peak intensities of the convex portion and the concave portion by an energy dispersion method (EDS; acceleration voltage is, for example, 20 KV). B / A = (Si strength of concave portion) / (Si strength of convex portion)

As is clear from the results shown in FIG. 3, the lubricity of the galvannealed steel sheet is good regardless of the ratio B / A. However, as for the oil surface adhesiveness, the ratio B / A is 1.2.
If it becomes less than 1, the ratio B / A is 1.2.
It is necessary to do the above. The preferred lower limit is 1.5
And more preferably 2.0 or more.

As described above, Japanese Patent Laid-Open No. 55-11078.
In Japanese Patent Laid-Open No. 3 and Japanese Patent Laid-Open No. 60-63394, there is a spot
To improve weldability, S on the Zn-based plating layer
iO _Two Although a plated steel sheet to which is attached is disclosed,
In order to improve spot weldability, they are
SiO_Two The purpose is different from the present invention because only the layer is formed.
Not only that, but if you look at the microscopic structure, SiO_Two leather
The film formation is completely different. That is, conventional
Plated steel sheet SiO_Two The coating is the same regardless of whether it is concave or convex.
Although it is formed with a thickness of the order of magnitude,
Is formed thick in the concave portion and thin in the convex portion.

In the present invention, silicic acid may use colloidal silica, but it is common to contain an alkali component such as Na ₂ O, K ₂ O and Li ₂ O for the reason of producing a colloidal solution. is there. Further, the silicate is SiO
It is a salt consisting of ₂ and a metal oxide, and has the general formula xM ₂ O · y
Expressed in SiO _2, usually sodium silicate represented by Na ₂ O · _{nSiO 2,} potassium silicate represented by K ₂ O · _{nSiO 2,} lithium silicate represented by Li ₂ O · nSiO ₂ is there. Therefore, regardless of whether silicic acid or silicate is applied, Na ₂ O, K ₂ O, Li ₂ is contained in the film.
It will contain an alkaline component such as O.

As a method of preferentially adhering silicic acid (salt) to the recesses on the surface of the steel sheet or the plated steel sheet, the concentration of alkali components such as Na ₂ O, K ₂ O and Li ₂ O in the silicic acid (salt) film is used. Is recommended to be below a certain value.
The uniformity and robustness of silicic acid (salt) depends on the Na ₂ O
It largely depends on the concentration of alkali components such as K ₂ O and Li ₂ O. The higher the concentration of these alkali components, the more uniformly and strongly the silicic acid (salt) is coated. Therefore, if the concentration of the alkali component is lowered, the uniformity and strength of the silicic acid (salt) film will be reduced, and the steel plate or plating layer will be more likely to come into contact with the adhesive or the chemical conversion treatment liquid. The processability is improved.

In order to coat the silicic acid (salt) as described above and effectively exert the lubricating action without deteriorating the adhesiveness on the oil surface, as described above, the weight of SiO ₂ after drying is from 1 to 1.
200 mg / m ² was applied, and (Na ₂ O + K ₂ O + Li ₂ O) / Si in the silicic acid (salt) film was applied.
It is recommended that the O ₂ weight ratio be 3% or less. The reason will be described with reference to FIGS.

FIG. 6 shows an alloyed hot-dip galvanized steel sheet with Si
O_Two 30 mg / m^Two SiO when applied_Two 
(Na in the film_Two O + K_Two O + Li_Two O) / SiO_Two Heavy
Graph showing the relationship between the amount% and lubricity and oil surface adhesion
It is. In addition, FIG. 7 shows that an alloyed hot-dip galvanized steel sheet with Si
O_Two SiO when applied_Two (Na in the film _Two 
O + K_Two O + Li_Two O) / SiO_Two % By weight and chemical conversion treatability
It is the graph which investigated the relationship of. The experimental conditions are as shown in FIG.
It's essentially the same as the conditions used to get the results,
Lubricity, oil surface adhesion and chemical conversion treatability are also evaluated in the same way.
Valued. In addition, Na in the film_Two O, K_Two O, Li_Two O, S
iO_Two Adhesion amount is Na, Li, K, Si concentration, fluorescence X
Calculated by line, ICP, or atomic absorption spectrometry
did.

As is clear from the results shown in FIGS. 6 and 7, alloying
The lubricity of hot-dip galvanized steel sheet is SiO_Two (N in the film
a_Two O + K_Two O + Li_Two O) / SiO_Two Weight%
Not good. However, oil surface adhesion and chemical conversion treatment
Is (Na_Two O + K_Two O + Li _Two O) / SiO_Two Wt%
If it exceeds 3%, it will deteriorate significantly (Na_Two O + K_TwoO
+ Li_Two O) / SiO_Two Weight% may be 3% or less
is necessary. The preferred upper limit is 1%, and 0.3% or less.
The lower one is more preferable.

As a method of preferentially adhering silicic acid or silicate to the recesses on the surface of the steel sheet or the plated steel sheet, Na ₂ O, K ₂ O, Li ₂ O in the silicic acid (salt) solution to be applied is used.
Besides lowering the alkali concentration etc., increasing the particle size of the SiO ₂ particles, making the shape of the SiO ₂ particles in a rod shape, it is also possible to control, such as by lowering the pH of the bath.

[0032] In the present invention, in order to further improve the lubricity, Zn oxide in the SiO ₂ film in, Ni oxide, Co oxide, Fe oxide, P oxides, B oxide, Ca oxide,
One or more oxides such as Mo oxide, W oxide and V oxide may be contained. The amount of these oxides deposited is 1 mg / m
^If it is less than ² , there is no effect of improving lubricity and 100 mg / m
^When it exceeds ² , the oil surface adhesiveness and the chemical conversion treatment property are deteriorated, so 1 to 100 mg / m ² (Zn, Ni, Co, Fe,
P, B, Ca, Mo, W, V).

Further, for example, press molding of automobiles is generally carried out with oil applied. Therefore, after applying silicic acid (salt) to the surface of the steel plate or the plated steel plate, 4
Oil having a viscosity at 0 ° C. of 5 to 50 mm ² / s may be applied. If the viscosity of the oil is less than 5 mm ² / s, the lubricity is not improved so much. On the other hand, if it exceeds 50 mm ² / s, it becomes difficult to degrease in the chemical conversion treatment step, and the chemical conversion treatability deteriorates.

The present invention does not limit the type of plating formed on the plated steel sheet. Examples include Zn-based plating, Al-based plating, Pb-based plating, Sn-based plating, and the like. Examples of Zn-based plating include hot-dip Zn-plated steel sheet and alloyed hot-dip Zn.
Examples thereof include plated steel sheets, electric Zn-plated steel sheets, electric Zn-Fe-plated steel sheets, electric Zn-Ni-plated steel sheets, and other Zn-based alloy-plated steel sheets.

In the galvannealed steel sheet, the Fe content in the plated layer is preferably 7 to 15%. 7
If it is less than 15%, a large amount of soft ζ phase remains, so that the slidability deteriorates, while if it exceeds 15%, the powdering property deteriorates.
However, even if the Fe content is in the range of 7 to 9%,
It is recommended to set the range to 9 to 14% in consideration of the fact that there are few phases but the slidability is slightly reduced.

The surface roughness of the galvannealed steel sheet is
The center line average roughness Ra (JIS B0601 standard) was 0.
5 to 1.5 μm and PPI (number of peaks of 1.27 μm or more included per inch, SAE, J9
11 standard) is preferably 75 to 300. still,
Here, PPI indicates the total number of peaks and troughs per inch of length for a size of 1.27 μm or more. The above-mentioned 1.27 μm is called a peak count level, and if the peak count level is reduced, naturally PP
Although the I value increases, in the present invention, in consideration of the convenience and reproducibility of the measurement, the peak count level of 1.27 μm, which is most frequently used, is adopted. Ra 0.5
This is because if the thickness is less than μm or less than 75, the galling is likely to occur on the sliding surface during molding, and the lubricity deteriorates. In addition, flaws during pressing become more noticeable. Ra is 1.5μ
When m and PPI exceed 300, the coefficient of friction increases and the lubricity decreases. In addition, problems such as deterioration of image clarity after painting occur. Ra is preferably 0.7μ as the lower limit.
m, PPI is 120, Ra is 0.7 μm or more, P
It is more preferable that the PI is 150 or more. On the other hand, the upper limit is preferably 1.3 μm for Ra and 250 for PPI.
It is more preferable that Ra is 1.1 μm or less and PPI is 200 or less. The surface roughness of the plated steel sheet can be controlled by the roll roughness of skin pass rolling after plating, the reduction rate of skin pass rolling, the roughness of the original plating plate, the Al concentration in the bath, and the like.

In the lubricating steel sheet of the present invention, a surface of a steel sheet or a plated steel sheet is coated with a silicic acid (salt) film. Specifically, the steel sheet is coated with a silicic acid colloidal solution or a silicate aqueous solution. Then, it may be formed by drying. The silicic acid colloidal solution is a dispersion of silicic acid anhydride fine particles in water using water as a dispersion medium. As the colloid solution, a commercially available product of colloidal silica or colloid sol (for example, Snowtex series manufactured by Nissan Chemical Co., Ltd.) may be used. Examples of the silicate aqueous solution include the above-mentioned sodium silicate, potassium silicate, and lithium silicate.

The method of applying the silicic acid colloidal solution or the silicate aqueous solution to the surface of the steel plate or the plated steel sheet is not particularly limited, and it is immersed in the above aqueous solution, a method of applying with a roll coater, or a method of applying with a spray. A usual coating method such as a method can be appropriately selected.

Further, in the present invention, it is desirable that the r value after applying the silicic acid (salt) to the steel plate or the plated steel plate is 1.4 to 2.3. If this r value is less than 1.4, cracking is likely to occur during press molding even if silicic acid (salt) is applied,
This is because when the r value exceeds 2.3, the effect is saturated and the manufacturing cost increases. The r value is a Rankford value, and is measured by applying a tensile strain of 15% using a JIS No. 13B tensile test piece.

The present invention will be described in detail below based on examples.
However, the following examples do not limit the present invention, and all modifications and implementations are included in the technical scope of the present invention without departing from the spirit of the above and the following.

[0041]

Example 1 A solution containing a predetermined amount of silicic acid (a colloidal solution of SiO ₂ ) or silicate shown in Tables 1 to 3 was applied to an alloyed hot dip Zn plated steel sheet using a squeezing roll. After coating, it was dried at 80 ° C. to form a hard SiO ₂ film. Weight of SiO ₂ after coating and drying, amount of SiO ₂ adhered on convex portion of plated steel sheet A
And the ratio B / A according to the SiO ₂ adhesion amount B of the concave portions are shown in Tables 1-3.
It is described together.

Regarding the plated steel sheet coated with silicic acid (salt) thus obtained, the lubricity (friction coefficient), oil surface adhesiveness (T-type peel strength) and chemical conversion treatability are shown in FIGS.
Evaluation was carried out in the same manner as the experimental method for. Tables 1 to 3 show these results.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

No. Nos. 1 to 57 are examples of the present invention, and are excellent in lubricity, oil surface adhesion and chemical conversion treatment. On the other hand, no. Nos. 58 to 62 are comparative examples when the weight of SiO ₂ is too small, and the lubricity is poor.
No. Nos. 63 to 68 are comparative examples when the ratio B / A is too small, and it can be seen that both the oil surface adhesiveness and the chemical conversion treatability are poor. No. No. 69 is a comparative example in the case where the weight of SiO ₂ is too large, and the oil surface adhesion and the chemical conversion treatment are also inferior.

Example 2 Various steel plates or plated steel plates shown in Tables 4 and 5 were coated with a solution containing a predetermined amount of silicic acid (salt) with a squeezing roll. After coating, it was dried at 80 ° C. to form a hard SiO ₂ film. Tables 4 and 5 also show the ratio B / A of the weight of SiO ₂ after coating and drying, the SiO ₂ adhesion amount A on the convex portion of the steel plate or the plated steel plate and the SiO ₂ adhesion amount B on the concave portion. The lubricity (friction coefficient) and oil surface adhesiveness (T) of the steel sheet coated with silicic acid (salt) or the plated steel sheet thus obtained were examined.
The results of evaluation of mold peel strength) and chemical conversion treatability are shown in Tables 4 and 5.

[0048]

[Table 4]

[0049]

[Table 5]

No. Nos. 70 to 95 are examples of the present invention and are excellent in lubricity, oil surface adhesion and chemical conversion treatment. On the other hand, no. 96-100 and No.
No. 108, 109 are not coated with SiO ₂ or S
This is a comparative example when the weight of iO ₂ is too small, and the lubricity is poor. No. 101-107 and No. 110 is a comparative example when the ratio B / A is too small, and it can be seen that both the oil surface adhesiveness and the chemical conversion treatability are poor.

Example 3 Various steel plates or plated steel plates shown in Tables 6 to 8 were coated with a solution containing a predetermined amount of silicic acid (salt) by a squeezing roll. After coating, it was dried at 80 ° C. to form a hard SiO ₂ film. The weight of SiO ₂ after coating and drying, and (Na ₂ O + K ₂ O + Li ₂ O) / SiO ₂ weight% in the SiO ₂ coating are also shown in Tables 6 to 8. Silicic acid (salt) thus obtained
Tables 6 to 8 show the evaluation results of the lubricity (friction coefficient), the oil surface adhesiveness (T-type peel strength), and the chemical conversion treatability of the steel sheet coated with or the plated steel sheet.

[0052]

[Table 6]

[0053]

[Table 7]

[0054]

[Table 8]

No. Nos. 111 to 177 are examples of the present invention, and are excellent in lubricity, oil surface adhesion and chemical conversion treatment. On the other hand, no. 178-182 are
Or SiO ₂ is not coated, it is a comparative example in SiO ₂ weight is too small, poor lubricity. No. 18
Nos. 3,184 are comparative examples when the weight of SiO ₂ is too large, and the oil surface adhesion and the chemical conversion treatment are also inferior. No.
Nos. 185 to 189 are comparative examples when the alkali concentration ratio is too large, and it can be seen that both the oil surface adhesiveness and the chemical conversion treatability are poor.

[0056]

EFFECTS OF THE INVENTION Since the present invention is constituted as described above, it is possible to provide a steel plate or a plated steel plate which is excellent not only in lubricity but also in oil surface adhesion and chemical conversion treatment. Moreover, since low-cost silicic acid (salt) is used,
It also has advantages such as reduction of manufacturing cost and improvement of productivity.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the amount of SiO ₂ adhered and the lubricity and oil surface adhesiveness.

FIG. 2 is a graph showing the relationship between the amount of deposited SiO ₂ and chemical conversion treatability.

FIG. 3 is a graph showing the relationship between B / A and the lubricity and oil surface adhesiveness in the SiO ₂ adhesion amount A on the convex portion and the SiO ₂ adhesion amount B on the concave portion on the surface of the alloyed hot-dip Zn coating.

FIG. 4 is an explanatory diagram showing a convex portion (a) and a concave portion (b) on the surface of a roughness curve of a steel plate or a plated steel plate (excluding alloyed hot-dip Zn plating).

FIG. 5 is a drawing-substituting photograph showing, in an EPMA observation image of an alloyed hot-dip Zn-plated surface, convex portions (a) and concave portions (b) on the plated surface.

FIG. 6 shows (Na ₂ O + K ₂ O + Li _{2 in the} silicic acid film)
O) / is a graph showing the relationship between the SiO ₂ weight percent and lubricity and oil surface adhesive properties.

FIG. 7: (Na ₂ O + K ₂ O + Li _{2 in the} silicic acid film)
O) is a graph showing the relationship between / SiO ₂ weight% and chemical conversion treatability.

[Procedure amendment]

[Submission date] February 21, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

[5] The alloyed hot-dip Zn plated surface by EPMA
It is an SEM photograph taken at the time of observation, and is a drawing-substitute photograph showing a convex portion (a) and a concave portion (b) on the plating surface.

Claims (7)

[Claims] 1. A lubricating steel sheet comprising a steel sheet or a plated steel sheet having fine irregularities on the surface thereof and a coating containing silicic acid or a silicate, wherein SiO ₂ in the coating is 1 to 200 mg / m ² and the amount of SiO ₂ adhered to the convex portion on the surface of the lubricated steel plate is A,
A lubricating steel sheet having excellent oil surface adhesion and chemical conversion treatability, wherein the value of B / A is 1.2 or more, where B is the amount of SiO ₂ adhered to the recesses. 2. Na ₂ O, K ₂ contained in the film
The lubricating steel sheet according to claim 1, wherein the total of O and Li ₂ O is 3% by weight or less with respect to SiO ₂ in the coating. 3. The coating comprises Zn, Ni, Co, Fe, P, B, Ca, Mo, W, V
The oxide of one or more elements selected from the group consisting of
The lubricated steel sheet according to claim 2, wherein the total weight of each element is 1 to 100 mg / m ² . 4. The viscosity at 40 ° C. is 5 to 50 mm ² /
The lubricated steel sheet according to any one of claims 1 to 3, wherein an oil of s is applied. 5. The lubricated steel sheet according to claim 1, wherein the plated steel sheet is a Zn-based plated steel sheet. 6. The zinc-plated steel sheet is alloyed hot-dip Zn plating having an Fe content of 7 to 15%.
Lubricated steel sheet described in. 7. The center line average roughness Ra of the surface of the plated steel sheet plated with the alloyed hot-dip Zn is 0.5 to 1.5 μm.
m, and PPI (1.
The lubricated steel sheet according to claim 6, wherein the number of peaks having a size of 27 µm or more) is 75 to 300.